The invention relates generally to an electromagnetic metal melt pump for pumping out and charging the molten metal from a furnace. The metals used in the furnace are, for example, zinc, tin, lead and, in some cases, aluminum, or alloys of these metals.
The invention is concerned more particularly with the pumping out and charging of such metals from the melting or heat storing furnace without the necessity of submerging the pump-body (inductor), supplied with electric windings, into the furnace. The removal of the melt using the pump according to the present invention and the charging step is accomplished in that into the melt, placed in the furnace, only a single suction snout is immersed, the cross section of which is relatively small in comparison with the opening of the furnace.
Several types of electromagnetic metal melt pumps used for the delivery of the melt and for charging such melt from the furnace, are known.
The German Pat. No. 2,304,257 describes such known solution, which is characterized in that at least one part of the pump must be emerged into the melt of the furnace, causing, thereby, an increased thermoloading for the windings of the pump. Such solution cannot be used with furnaces having a narrow opening, because the part of the pump which is to be immersed into the melt, cannot get into the furnace through its opening.
Another solution also directed to the delivery of metal melts using electromagnetic pumps is described in the periodical "Giesserie 69" (GFR, No. 20, Sept. 27, 1982, pages 575-579). According to the last mentioned proposal, the pump is not directly introduced into the metal melt, but it is directly connected to the furnace. For the operation of such pump with a closed furnace, inert gas pressure is used and must be increased by means of an auxiliary outside equipment in order to force the melt into the pump. This requirement can be fulfilled only by the use of a pressure tight furnace, which makes the furnace construction very expensive. During interruption of the delivery, the pump drops the metal melt. Such dropping of the metal melt can be avoided by the use of a foot valve, or by energizing the pump with a predetermined power. To produce a special foot valve for metal melts, is not a simple task, because an adequate enerization of the pump may easily have the consequence, that the metal melt becomes overheated.
The common advantage of the electromagnetic metal pumps is that no moving structural components should be used. The power necessary for the delivery of the metal melt is produced by the electromagnetic field. If the drawbacks of the prior art pumps could be eliminated, the field of application for the electromagnetic metal pumps could be considerably enlarged, and thereby simpler, less expensive and safer and more economical metal melt pumps could be produced.